This invention relates to apparatus for forming a seam between a can end member and a can body member, after the can body member has been filled with a liquid, to affix and seal the end member on the body member.
In recent years, there have been new developments in opening devices for metallic cans which are integral with metallic can end members and include "tab" type opening devices openable by axially inwardly directed forces causing axial inward movement of the tab portion relative to the end member after fracture of score groove portions connecting the opening device to the end member. Such opening devices preferably remain integrally connected to the end member after opening to preclude removal and careless disposal thereof. Such opening devices are preferably also designed to be opened by manual application of relatively low forces, e.g., 8 to 14 pounds, and preferably by directly applied manual force through the finger of a person rather than by mechanical advantage devices in order to reduce the cost of manufacture. Such an opening device is disclosed in U.S. Pat. No. 3,982,657.
The construction and arrangement of such opening devices have created problems in the manufacture of cans because of the relatively low forces required to open the devices. In conventional can manufacturing operations, a can body member and a can end member are separately constructed and then combined after the can body member has been filled with the contents to be stored within the completed can. In order to provide a can opening device which will satisfy the requirements of being openable by relatively low manually applied force, it is also necessary that suitable handling and processing methods and apparatus be devised to preclude premature opening of the opening devices during the manufacture, filling and subsequent handling of the can components and the completed can.
The present invention relates to the solution of particular problems in conventional "seamer" apparatus for the manufacture of cans which apparatus sealably affixes a can end member to a can body member filled with a fluid such as beer. The problems solved by the present invention involve not only the prevention of premature fracture of new can opening devices but also involve related and other problems associated with conventional seamer apparatus, regardless of the design of the opening devices and end members, including mounting of certain parts in a manner preventing undue wear and breakage and contamination of such parts resulting in unnecessary down time of the apparatus for repair, maintenance and cleaning.
The present invention may be summarized as comprising seamer apparatus having a lightweight control rod means with a resilient compressible cushion means on one end thereof for engaging the upper surface of an end member at various times during operation of the seamer apparatus and spring means acting in combination with the cushion means to apply only a relatively light force on the end member less than the normal manually applied opening force while nontheless providing all the requisite functions of holding and stabilizing the end member in the seamer apparatus. In addition, the control rod means is constructed and arranged to reduce wear and tear problems, to facilitate maintenance, and to reduce contamination of the apparatus.